Except as to the authority delegated by § 0.147, the authority conferred by this subpart X upon heads of organizational units may be redelegated by them, respectively, to any of their subordinates. Existing delegations of authority to officers and employees and to U.S. Attorneys, not inconsistent with this subpart X, made by any officer named in this section or by the Assistant Attorney General for Administration, shall continue in force and effect until modified or revoked.